Train control system



Nov. 7, 1933.

A. G. WILLIAMSON TRA-INCONTROL SYSTEM Filed Aug. 25, 1927 5 Sheets-Sheet l @331g O @Home/n l Nov. 7, 1933. A. G. WILLIAMSON 1,933,780

TRAIN CONTROL SYSTEM Filed Aug. 25, 1927 5 Sheets-Sheet 2 DRIVE/v FRaM A TRA/N AXLE 5,0

Nov. 7, 1933. A. G. WILLIAMSON TRAIN CONTROL SYSTEM Filed Aug. 25. 1927 5 Sheets-Sheet 3 www Nov. 7, 1933. A. G. WILLIAMSON TRAIN CONTROL SYSTEM Filed Aug. 25, 1927 5 Sheets-Sheet 4 Nov. 7, 1933 A. G. WILLIAMSON TRAIN CONTROL SYSTEM Filed Aug. 25 1927 5 Sheets-Sheet 5 Patented Nov. 7, 1933 TRAIN CONTROL SYSTEM ArbaG. Williamson, Carnegie, Pa.,- assigner, byy

mesne assignmentsfto The Union'Switch &'

Signal Company, Swi of Pennsylvania Application August 25,

l 17 Claims.

Fig. l Aisa diagrammatic View of track-Way l0 and cabmeans emb vention. l

Fig. 2 is a diagrammatioview oia modied .form of cab means-to be used in place of the corresponding parts shown in Fig. 1. Y

3 is a diagrammatic View of a second modilied form of the cab means shown in Fig. l. Fig. 4 is a diagrammaticview Vof ntrack-Wayr and cab means embodying'a more complex form of the invention. Y

Fig. 5 is a diagrammatic View oiltrack-Way and cab means showing another complexiorm oi the invention. f Fig. 6 isa diagrammatic viewv of a modified form of tra-e the corresponding parts shown in Fig. in the 4'simple exemplication of the invention illustrated in Fig.. 1, the indicating means may be either signals or brake-setting means or both and may be considered as being represented bymagnet valve M. From another point of View magnet valve M and/or electron tube E" may odying one form of the inbe considered as a train-carried translatingA device which` is controlled by two opposed sources oi power here representedby battery SB and generator SP. SP is, in instance, a magnetogenerator or thepermanent magnetic type and the voltage generated by` it' directly `proportional to its speed. This generator supplies voltage Ydirectly proportional to l the speed of the train in miles per hour by being driven from an axle or other moving part of the train, and the gear ratio is here oi such character t at at seventy miles per hour thirty vered, at thirtyiive miles per'hour n volts are delivered, and at fifteen miles our and one half volts are delivered, by

enerator. erator SP andbattery SB. are included in id-filament circuit of electron tube E so arranged that the voltage Vsupplied two power sources oppose each other as vident from the plus and minus signs era SP, is connected to filament 38 of tube E" means of Wires 48 and-37, and the negay means of a simple leway means to be used-in place of,

in 1. The positive brush, oi 'gen` ssvale, P'a., afcor'poration 4- 19.27. Serial No..215,318.f

tive brush is connectedv to grid 49 of tube E Vby of Wire 50, resistance 53, Wire 63 or 55, depending upon the position Vof armature 74, and Wire 57. iResistance 53 is connected across the terminals of battery SB, and has two taps 62 and 54. Let us assumethat vthe voltage of battery SB is-thirty-two volts and ,that tap 54 is so located that/.the drop between 54 4and 105 is thirty volts; Therefore, as longas armature 74 is the rlgnt'hand position (Fig. 1) grid 49 of tube"Ef willfrbe thirty volts positive with respect to filament 38'-so far as resistance, 53 and battery SB are concerned. Let vus further assume that tap 62 is so located thatthe drop` between 62 and V105 is six and one-half volts, so that Whenever armature 74`is in the lefthand position (Fig. 1) vgrid'49 of tube Ef yis six and one-half ,volts positive With respect to filament Sii-so far as re concerned.,y l

As previously set forth,'generator SP develops lthirty `volts rwhen the train is traveling at a speed of seventy miles per houry and this voltage supplied to the lamentof E opposes the Voltage supplied by battery SB via tap 54 and wire 55, armature 74 and wire57 .-togrid 49. Therefore,` so long as the speed of the train is below seventy-miles per hour, grid,49y Willbe positive with respect to-iilamentBS; 1f the speed is seventy miles perhour. there will be no difierenceV inY potential andif it rises .above seventy miles-,per hour grid 49 will be negative With-re-v spect to lainent 38. YIfarmature 74 Vis in the left-`hand position then battery SB supplies only sixand one half votes to grid 49 viaftapSZ',` Wire 63, armature .74 and Wire 57, and the same relation that exists between thirty volts supplied by; generator SP and thirty volts supplied by Way of tap 54, Will prevail as between six and one half volts supplied by generators? and a like number of volts supplied rby Way oi tap 62.

Electron tube E isa three element'tube having plate'104, grid 49 and filament 38, the latter heated.` by batteryv FB',A andhas, in addition to the grid-filament circuit already described, a. platelamentcircuit here consisting of the'following elements: Batteryv HB, Wires 41 and"102, magnet valve M, `Wire 103, plate 104, ilament 38, wires 3'?, 39 'and 44 back to battery HB. We will assume that the voltage delivered by battery -IBl and the resistance oi the coil of M are suchthat, when grid 49 has apositive Vpotential of thirty volts With respect'toflanrient sistance 53v and batterySB are.7

los

Ythe value ofcurrent flojW'in the plate-lila?` Y ment `circuit is .040V amperes, and that when grid livered by generator SP is equal to or overcome the voltage suppliedby battery SB, the coil of Y said magnet M is not sufciently energized to hold its armature up. In other words: in the example of values given, and With armature. 74 in the right hand position (Fig. 1), when the speed of the train reaches or exceeds seventy miles per hour a circuit controlled by M is opened. So likewise when armature 74 occupies the left hand position (Fig. 1) so that only siX and one half volts are deliveredv to grid 49` byv battery SB via tap 62 then if the speed of the train reaches or exceeds,V say fifteen miles per hour, the value of current flow in the plate-filament circuit will also drop to .010 amperes and magnet M will become sufficiently deenergized to release its armature.

I `have assumed a circuit to be controlledby M and such circuit may in turn control a signal or a brake setting valve or both, or, in accordance with practic'ein the art it may control a fluid circuit and may in itself constitute means to actuate eitherI a signal or the brakes as will be understood.

Any suitable means may be employed to. intermittently or otherwise control armature 74 in response to a change in traffic conditions of the track-way, but, preferably, such means exercise a continuous control and include the tranic rails. As here shown by wayof illustration, armature 74 is polarized and is controlled by relay R which later is included in the platefilament circuit of electron tube E, said circuit being as follows: From battery HB, to wire 41, coil'of relay R, wire 42, plate 43 of tube E, lament 23 of the same, andwire 44 back to battery HB. Electrony tube E is here a three-ele` ment tube and contains a grid 22 in addition to*V ythe plate and filament previously described.

Filament 23 is heated by battery FB. Tube E has a grid-filament circuit composed of coils 14 and 15 (carried in series by train 4' and in inductive relation to traffic rails 1 and 2)v Wire 19, condenser 20, wire`21, grid 22, filament 23, vwire 24 and back to coils 14 and 15. 25 ,lis a tuning condenser bridging'this circuit. Traffic rails 1 and V2 are arranged in blocks, A, B, Cetc., by suitable insulation and said rails are ,supplied with. a track-circuit hereconsisting of a battery 7 connected through impedanceV coil 13 to the rails at the outgoing end of-each block, and a-track relay Ra (or Rb etc.) connected to the rails at the ingoing end of each block. The traffic rails are supplied with a second current derived from generator D over suitableline wires to` track transformers Tb, Tc etc;, the circuit from each transformer to the rails being as follows: secondary 7 is connected to rail 1 by means of wire 8,. resistance 8 and wire 3; and to rail 2 by means of Wire 5, armature l2 A(under controlof a relay as Ra of the block in advance) and wire 6. The impedance coil 13 serves to choke the ow'of alternating current without impeding the flow of direct current, and resistance 8 serves to prevent a short-circuiting of the battery by the secondary of the track `transformer. Track 'relays Ra, Rb are of` theV direct current type and therefore respond only to current supplied by battery 7 and not to current supplied by the transformer. When a train as 4 is in a block, as B, track relay Rb is shunted thereby dropping armature 12 and opening the circuit from transformer Tc in the block behind. Current from transformer Tb is likewise shunted by the Wheels and axles of the train andwill induce a current flow in coils 14 and 15 and therefore inthe pick-up or gridlament circuit of tube E renderingV the grid negative. This will choke down the current in the plate-filament circuit from a value of 1.00 to a value of 0.40. Should a train now enter block C, then the coils 14 and 15 of such second train would have no current induced in them and consequently the Value of the plate-filament circuit current would rise from 0.40 to 1.00. So also should the second train enter block B while the latter is still occupied, no current would be4 induced in coils 14 and 15 of Vsuch second train. Relay R, included in the plate-filament circuit of tube E, is a direct-current polarizedv relay and is so biased that, with no current or a very weak current flowing in the plate-filament circuit, armature 74 will always revert to its left hand position (Fig. 1). With a direct current of the proper polarity and of the proper value,-

say 0.40, owing, thenarmature 74 is forced over to the right-hand position (Fig. l); and with a current'of higher value, say 1.00, flowing armature 74 is again forced back to the lefthandV position. Tube E therefore acts as a detector, the detail description of which, together with afull disclosure of the construction of all the parts, and of alternate forms, is disclosed in application Ser; No'. 147,403, led November l0, 1926. l

It will now be evident that under safe trailic conditions relay 74Y will be in engagement with contact -75 and that the, train can run 'unhindered up to a speed of say seventy miles per hour, but thatA if this speed is exceeded train control, whatever its character may be, will be initiated. So likewise, under adverse traiiic' conditions, relay 74 will be in engagement with contactj93 and the train can then run freely up to a speed of fifteen miles per hour but not higher without initiating train control.

`I desire'it Vto be distinctly understood that when the invention isembodied in a construc-v tionin which an electron tube as E is employed to control an iniiuence from the track-Way, it is not essential that said electron tube be used merely as a detector in the manner outlined above.' It may equally as well be utilized as an amplifier if so desired. Fig. 2 shows such an arrangement. In this form of the linvention the track-way equipment-is not shown but it could be the same as that of Fig. 1. The circuits associated with tube E could also be the same as those of Fig. 1, but' relay RR is here an alternating current relay and-condenser 20 ofthe pickup circuit of tube`-E could be omitted, or, it might be a leakyl condenser as will be understood. With this construction, current from battery HB will not pick up armature 74a of relay RR but when an alternating current is induced in coils 14 and 15 and in the pick-up circuit of tube E the grid thereof is alternately a made positive and negative thereby imparting an alternating component to the current flowing in the plate-filament circuit of tube E, and the Here, linstead oioattery SB tnere is utili.

Yplate-iilament circuit oi tube `per hour M will remain energized.

It is not desired under all circumstances to have a construction that gives an indication in` the cab of the train or which controls its speed under clear traido conditions. En suoli eases', the very simple form of the inventioneiiown in Fig. 3 may' be employed. In tliis oonstruetion the track-way equip-nient may t1 f siicwm in connection with Fig. l, and the caio ee also Substantially Athe same as thatV e; the main difference being that resistance its taps are omitted. in Fig. battery a'voltage of and one?. i volts and as negative polev connected to eontaot so that when armature '74 is in the right (Fig. 3A) said negative pole oonneeted to ment 38 of tube E". Tile positive pole of bat-l tery YSB is conneoted to grid of Juoe E. Magneto SP has its negative lfruslleonneoted to the negative pole of battery SB and it i brush connected to VVeontaot "Ui traie conditions, armature 'ifi will l.- right-hand position (Fig. 3) and battery Coi the otherhand, trarne conditions are ou;l

armature 74 moves into engagement with` eentaot 93 and th Voltage developed l ,7 SF be` comes opposed to that of battery Sl and. ii at fifteen miles per hour magneto SP generates six and one half volts, tiren therewill oe no diierenoe of potential between grid i9 and fila-Y ment 38 and therefore a current oi insuiioient value to properly energize M will new in the E" t and train control will be initiated.

In Fig. 4 is shown a somewhat more elaborate fornirci' the invention than is shown in. l. ed a may Conveniently be a lee els generator G (which headlight turbo-generator) oroes the 5l and 52 of this generator is p Y 53 having three taps and that are eonnested to Wire 57, under diferent traffic oon tions, which Wire leads to grid 49 oi and with its negative brush. by wire 5G to 52 leading from the negatieve side oi G. Let us assinne that at seven*j hour magneto SP delivers thirty volts, ive miles per hour fifteen volts and miles per hour six and one-half Volts and t taps 54, 58 and S2 are so loeeted with respectto point that generator W. voltages. When relai,7 X i.' ,ei

55 Will be in the uri-position and Will therefore be supplied from l 55, armature and wire 5"? to grid fore so long as the train runs below seventy niiet W1 en relay Y is energized, armature 50 will oe position and iteen Volts will thereto-1 plied from tap 58 over Wire arniatur 61 and. 57 te d e9 an therefore so l Y 3 DE suptrain runs below tiiirty nve peri1 remain energized. Wnen rel y Z i: ei,

arma-ture 64 will be in the tip-position andsix and one-half volts will isle supplied troni tap over Wire 63, armature 6e and wires 6i. 57v

the upremain energized. f

instead oi' battery HB ofFig. Vltliere is e oloyed in the construction of aine-tor.

-fenerator MG having reotor i109 energized 'r 4gener .tor Gini i leans oi leads 5l 52.

.ment eireuit voi 46, W es el, i5 and filament 38, wires As the construerig. fi gives tiiree position indise present oase, emploi/eden in addition to tube E and Jo that are i' e`iuded in the plate oi tubes E E m winding i0 as lay R,

wire

ioliows: Winding 4D, wire 41, Wire '42, plate 43' of tuoe E, iila- 36, filament 32,v Wire 37, iliawires Si? and ill baciato 'Windanti again fron"wire` el to Wire 45, relay wire e6, platef' of tubev E', ent Bi. 'and so "oaok to winding e0.

and it are of the saine character as E oi Fig. l and it will be understood. that loi f current oi an intermediate value oi say iiows in the plate-filarnent circuits oi tubes E. and Ef said relaysv remain energized to hold eturee 58 in the rig "it-hand po- (rig. ll) 'but that if current :eitlfier infwith respect to this-value e tube E armature 'le oi to its leit hand (Fig. LJ and tube armature 68 will 'inove to osition 4). Tile larnents u and aan conveniently be eneratorwino.' e Sliover the fol# e 35 lament 23 j Wire iilanent Sii, 3*?, filament if new ourH longer flows that is, t our t inislied, 68 will with Contact 7'! and the theseY circuits can Conveniently be energizedr torgrid 49 and thereioreso long as the train does not exceed fteen miles per hourv M will" ire- 39 back to Winding 3e. Said windit so happens that, in` this particular construction shown, a manual act is required on the part of the engineer to energize relay Y. 'This manual act consists in raising push button PB to momentarily close the contact at 83, when current will now over wire 84 to coil of relay Y and from the latter by wire 85A to wire 72 and so back to winding 34. The engineer immediately returns push button PB into engagement with contact 79 but relay Y having been energized, will remain so by reason o the fact that armature 87 has been picked up and current to said relay will continue to flow from wire 86, arma-- ture 87, wire 88, coil of relay Y and wire 85 to wire 72. The energization relay Y also raises armature 60 thereby permitting the thirty-five mile per hour speed. In other words, if armature 68 of relay R moves to the left hand position (Fig. 4) then caution or yellow light81 will be displayed and ii the engineer does nothing the brakes will be applied .by M but if he is on the alert and manipulates push button PB he may proceed at a speed up to thirty-tiveA` miles per hour without any application of the brakes by M. If now current of an intermediate Value no longer nows through the coils or" relay R, that is, the current is either increased cr diminished, armature '74 will move into engagement with contact 93 andthe circuits through lamp 71 and relay X or through lamp 81 and relay Y, as the case may be, will be broken and another circuit will "ce established as follows: from Winding 34 to armature 74, as previously described, then contact 93, wire 90, push button PB', Contact 91, wire 92, danger vvmoves push buttonPB' momentarily into engagement with contact 96, then a circuit is es tablished from wire 90, push button PB', contact 96, wire 97, coil of relay Z, wire 98, to wire 72.v

ated with relay Z is also an armature 107 and a Vpartial circuit, from wire 78 to wire 72, .ccn-

sisting of wirelO, armature 107, wire 108, coil of relay Y and wire 85. The function of this partial circuit is to energize Y automatically when passing from danger to caution and requires no intervention by the engineer. It is to be noted that whenever the engineer operates the respective push buttons PB or PB' the respective signal during the interval that vthe respective contact 79 or PB or 91 of PB is open.

The invention residing in the control exercised by relays R and R' over relays X, Y and Z and the circuit arrangement including circuit closers or push buttonsvPB and PB is independent of any particular construction or type of speed ccntrolling means such for instance as herein disclosed. It will also be evident that relays R light 81 or 94 will be eirtinguished both coils in the same manneigthis beingin contradistinction to the arrangement oi coils 14 and 15 which are so wound that'to be eiective current must' iicw in series in rails 1 and. 2, that is, down one rail in one direction and up the other rail in the other direction. The gridlament circuit of tube E' is as follows: coils 16, connection 26, coil 17, wire 28, condenser 29,

wire 30, grid 31, filament 32, wire 33 and back to` coil 16. 27 is artumng condenser bridged across the circuit. Track circuitsmay conveniently be used in connection with tubes E and E' and theirv grid-iilanient circuits as follows: trailic .rails 1` and 2 are arranged in blocks AVB, C, etc.by means of insulation 3 or otherwise. D is a generator supplying current over line wires to track transformers To, Tc, etc. Secondary 400 at the outgoing end of a block supplies current to rails 1 and 2 in series over wires 5 and 6 and Rb is a track relay at the ingoing end of the block and also connected in series with the rails. The current supplied by secondary 409 not only energizestrack relay Rb but also induces a current in' coils 14 and l5 and their circuit. Secondary 122 is connected to rails 1 and 2 in parallel by means of wire 113, Contact 114, armature of track relayRa of the block in advance, wire 117 center tap of bond 113, down both rails 1 and 2, to center tap-of bond 201 and then by wire 119 back to secondary 122. rihe current of thiscircuit energizes coils 16 and 17 and their circuit;

Now it will be evident that, when a train enters an unoccupied block, asB, and the block in ad` Vance is likewise unoccupied, the grid-iliamcnt circuits of both tubes E and E' are energized and both grids are rendered negative. IThis vchokes down the current in the plate-lament circuits, including coils of relay R and R', to an intermediate value. Therefore armatures 74 and 68 are both in the right-hand position (Fig. 4). If a train is inthe block in advance (A), then track relay Ra will become deenergized, armature 115 will drop and secondary 122 will no longer supply current to the rails of block B. The result of this isthat coils 16 and 17 will no longer be energized, the value of the plate-filament current of E will rise above the intermediate value and relay R' will be so affected that armature 68 will move to the left-hand position (Fig. 4). 1f a train should already be in block B when a second trainenters that block, then coils 14 and 15 `will not be energized and consequently the value of the current not ing in the plate-'filament circuit of E will rise above the intermediate value circuits whereby the manual intervention of the engineer is rendered unnecessary and another modification involving a diierent use of electron tubes E and E and the trackuvay circuits.- Taking up the latter modification first, Tl) indicates a track transformer Which is so designed With respect to its iron core that its secondary 4l gives a current Wave-shape that has a pronounced third harmonic component as Well as a fundamental component.

The leads from secondary '401 to the rails are controlled by the track relay oi the block in advance, such'relay being indicated at Ra. When block A is unoccupied and there is a train, as 4, in block B, then armature 402 of Ra Will be vup and the -Yfollowing circuit will be established: irorn secondary 431, to wire 424, armature 402, contact 493, non-inductive resista-nce 4Gb, Wire 4&6, rail 2, Wheels and axles of 4, rail 1', and Wire 437 back to secondary 401. Whenblock A is occupied and relay Re is deenergia-ed armature 462 will be down and the following circuit will be establishedfor a train occupying block. B: secondary 401, Wire 404, armature 492, contact 433, Wire 499, impedance coil 410, wire rail Y2, Wheels and axles of 4, rail i and Wire 497 back'to secondary 401. Ii a train is already in block B When a secondary train enters, then no cu nt will passte the secondL train. When current passes from secondary :t-l via non-inductive resistance 495, its Wave-torni will be such that it has a fundamental component and a pronounced Vthird harmonic component, Whereas if said current flows via impedance coil 410, which is given a high induotance .relative to its ohniic resistance, then said third component will be largely suppressed, that is, it will no longer be eiTective. OnV the train, pick-up coils 14 and l5 are in series with primary windings of transformers TI and T2, the secondaryof T1 beinfr include vin series in the grid-lanient circuit of tube E,

and the secondary oi T2 being included in series The the grid-filament circuit of tube E is tuned, by means or condenser 25, to the frequency of the fundamental component ci the rail circuit, andr the grid-nlarnent circuit of tube E' is tuned by means of condenser 27, to the frequency oi the pronounced third harmonic component of the rail circuit. .It therefore a train enters block B and it as .Well as the block in advance are both unoccupied, then the rail current has both a fundamental and a third harmonic `component and both tubes E and E will be iniluenced to hold armatures 74 Yand 68 oi relays R and R in the right hand position (Fig. 5). yItthe block (A) in advance is occupied, then the pronounced third harmonic component is absent and onlyv the fundamental is present and consequently only tube E will be affected. If no current is present in the rails neither tube will :be affected. y to further describe thev V,PLV together With their circuits are omitted. To nir-.lie the matter plain, signal 8l is connected directly, by rneans of WireSS, to Wire 73, and relay Y,V is likewise connected directly, by Wire to Wire 7S. to Wire by Wire 92' and relay Z is similarly determined by the speed'oi the train. Y.

So also, signal 94 is connectedV connected -by ineans of Wirel V92". The result. or" this is that When-armatures Z4 and 63 are both in theright hand positionk (llig. 5) signalV lanip 'Il and relay X are automatically energized, Whenarinature 74 is in the-right hand position and 68 in theleit hand position (Fig. 5) signal .3l and relay Y are bothautornaticaliy energized, vand when armature 74 is in theleft hand posiinally deenergized by reason of the iact that its circuit is controlled'V by baci: contact r oflocal block relayrRb and by front VContact r ofI relay Ra of! the block in advance. When a train enters block B from the right, and blocks A and E are both unoccupied, relay 423 becomes energiaed by dropping. oi armature r of relay The lifting of the armatures otrelay 423 l disconnects battery 42o troni the rails and closes `acircuit from battery 424, along Wire 425, armature 426, wire 427, motor 423, Wire 429, armature 43u and Wire 431 to battery 424 vthereby Vdriving motor 423. The shaft oi Vmotor 428 carl ries `a coinniutator or interrupter so that when relay 423 is energized and motor.428 running, interrupted current Williiowirorn battery 424, along wire 425, armature 426, Wire 427, conirnutator 432, Wire 433, armature 434, Wire 435, l1 rail 2, train-shunt, rail l, wire 436, armature 437, Wire 433, Wire 429, armature 430 and Wire 431 baci; to battery 424. The interrupted current thus ilowing in the rails induces a'current in coils14 and 15 (Fig. l) and, so long this curl flows M will be energized. If block A is occupied when a train-enters blecir` B, then relay Ra will bedeenergized and the circuit through relay 423 Willnot beclosed and the interrupted current Will not be supplied to the rails. It a l train is already in the bloei: Whentlie second `train Yenters, then said second train will receive no current, the iirst train absorbing it all.

I claim:

l. In a train control system: a train, a traini carried translating device,` and two opposed 'sources ofpower, the voltage of one or" which is determined-by the speed of the train and the supplied voltage of the otherof which is controlled by traino conditions, to control said translating device. z

2. In a train control systern: a train, a traincarried translating device-circuit means for said translating device, two'opposedsources of power, included in said circuit nieans,the voltage ofV one'. l ci which power sources is determined by the speed of the train, and trailc-controlled'meansv to vary the circuit ineans to Ythereby control the voltage' supplied by fthe other povverY source...

3. In a train control system: a train, an elec- '1 tron Vtube having a grid, and means to control Vthe potential of the grid including: two opposed sources of power, the voltage ottone orf which is `In iatrain control system: a' train, anelectron tube having a grid, and meanstocontrcl the potential of 4the grid including :(,two opposed sources of power, the voltage oi. one or which is determined bythe speed of the train and the 1 vli) trolled by traiic conditions. j

5. In a traincontrol system: ra train an electron tube having a plate, a grid and a filament,

agev oi' one of which is determined by the speed of the train. i

6. In a train control system: a train,v an electron tube having a plate, a grid and a filament, grid-filament circuit, and two opposed sources oi power in said grid-filament circuit, the voltage of one of which is determinedgby the speed or the train, and the supplied voltage ci the other of which is controlled by traflic conditions.

7. In a train control system: a train, an electron tube having a plate, a grid and a filament, a grid-filament circuit, two opposed sources of power in said grid-lament circuit, the voltage of one of Vwhich is determined by the speed ci the train, a plate-filament circuit, and a translating device included in said plate-*filament circuit.

8. In a train control system: a train, an electron tube having a plate, a grid and a filament,

a grid-lament circuit, two opposed sources of power in said grid-filament circuit, the voltage of one or which is determined by the speed or" the train, and the supply voltage of the other of which is controlled by traine conditions, a plate-filament circuit, and a translating device included in said plate-lament circuit.

9. In a train control system: a train, a traincarried translating device, circuit means for controlling said translating device, two sources of power, included in said circuit means, the Voltage of one or" which power sources is determined by the speed of the train, and traiilc-controlled means to vary the circuit means to thereby control the voltage supplied by the other power source.

10. In a train control system: a train, an electron tube having a grid, and circuit means to control the potential of the grid including: two sources of power, the voltage of one of which is determined by the speed of the train. v

1l. In a train control system: a train, a traincarried translating device, two sources' or power ior controlling said translating device, the voltage of one of which power sources is determined the speed of the train, traino controlled means to vary the voltage supplied bythe other source, and manually*operated'means to render active the control of said two sources oi power over the translating device under certain tra-rdc conditions.

l2. In a train control system: a trackway, a

train, a train-carried translating device continuously responsive to trado conditions of said trackway, a second train-carried translating device controlled by two sourcesroiC power, the

lating device and the second indicating devicek controlled by the second translating device.

13. In a train control system: a trackway, a train, two train-carried translating devices, one responsive to traffic conditions of the trackway,

`and the other responsive to a'control derived I 1,933,780 supplied voltage of the other of which lis confrom two sources of pow'eiivthe voltage of one of which is determined by the speed of the train and the applied voltage of the other of which` is determined by the first-mentioned translating device, and a train indicatingv device controlled by the second-mentioned translating` device. V

14. A continuous indication code system for the control of railway Vehicles, comprising a stretch of track divided into insulated blocks, a closed track circuit for each block, a normally inactive rotary motor and a source of electrical energy adjacent each block junction, circuit controllers operated by said motors adapted to connect said sources o cross the rails at the exit ends of the respective blocks to cause current impulses arranged in a predetermined code to flow through the rails when the motors are operating, means for setting the motors in operation when and only when` the respectivel track circuits immediately in rear thereof are short circuited or interrupt-l in combination with a vehicle traveling on the track having a translating device responsive to the current impulses and code responsive iechanism acting in conjunction with the t nslating device to effect-a clear indication so long as said code is being received.

15. ,a continuous train control system'including: tr rails arranged in blocks, trackway no apparatus operating under proceed tralc cond ns to su; oly interrupted current across the traino rails at the exitend of the block, a train, a circuit controller on the train capable of assuming different positions, and train carried apin an inductive relation with the traffic including means to cause said circuit conto assume relatively quickly one position butA relatively slowly another position to thereby retain the circuit controller in the one positionas long as said interrupted current is supplied to the traic rails.

16. A continuous train control system including: traic rails arranged in blocks, trackway apparatus operating underproceed traffic conditions to supply interrupted current across the traino rails at the exit end of the block, a train, a circuit lcontroller on the train capable of assuming different positions, and train carried apparatus, in an inductive relation with the traiiic rails, including means that quickly assume one condition and relatively slowly another condition to thereby retain, the circuit controller in a given position as long as said interrupted current is supplied to the trailic rails.

17. A continuous 'train control system including: trariic'rails 'arranged in blocks, trackway Y apparatus operating under proceed trafilc coninterrupted current across the dition-s to lsupply traido rails at the exit end of the block, a train, a circuit controller on the train capable of assum one or another of two circuit closing positions, and train carried apparatus, in an inductive relationV with the trafic rails, includling means to cause said circuit controller to assume relatively vquickly'one circuit closing position but relatively slowly the other circuit closing position to thereby retain Ythe circuit controller in the one position aslong assaid interrupted current is supplied to the traffic rails.

ARBA G. WILLIAMSON. 

